Who would have thought it? Alistair Darling has been the occupant of 11 Downing Street during the biggest economic bust in Britain's postwar history, yet it was George Osborne who had it all to prove in last night's debate.

All things considered, the shadow chancellor didn't do badly. Sure Osborne looked pleased with himself, as he always does, but he made Darling admit that Labour was dropping the idea of a "death tax" to pay for long term care, and fess up to nicking the Conservative plan to raise the threshold on stamp duty in last week's budget.

Not that the youngest of the three men who would be chancellor had it all his own way. He had his own spells of wriggling when put under concerted pressure over the latest attempt by David Cameron to reverse the Conservative slide in the opinion polls – lower national insurance contributions.

It was, if you get your kicks out of re-regulating the banks or the right time to tackle the deficit, rattling good fun, even though Darling, Cable and Osborne all appeared to be dressed for a reunion of undertakers. The sombre attire, presumably, was to show how all three took the challenge of cutting the budget deficit. But, apart from Darling's backtracking on the death tax, there were no bombshells and little to stop the apathetic voter switching to Coronation Street, EastEnders or Raymond Blanc's kitchen secrets.

There may be many more times in the next five weeks when the viewers grope down the back of the sofa for the remote, for this – rather than the moment Gordon Brown goes to the Palace to see the Queen – was the moment the bell rang for the start of the fight.

And it was Osborne who was under the most pressure to deliver.

After a shaky start to the crisis,Darling has had a good war and is close to attaining national treasure status. Vince Cable, one of the few at Westminster to have warned in advance of debt-fuelled consumerism, has already been elevated to that status. And Darling and Cable were quickly on the attack. After a bit of shadow boxing in which they and Osborne bragged about their credentials to do the job – tenacity (Darling), energy (Osborne), getting it right (Cable) – the debate quickly turned to the shadow chancellor's planned cut in national insurance contributions.

Darling dropped his normal rope-a-dope approach and came on aggressively, warning that Conservative plans for immediate spending cuts risked "tipping us back into recession". Cable, who had all the night's best soundbites ("pin-striped Scargills" to describe the bankers being the best of them) and got nearly all the laughs from the carefully vetted Channel 4 studio audience, said the proposed war on waste that Osborne claimed would pay for lower NICs was fictional. The Liberal Democrat Treasury spokesman wasted no opportunity to remind the audience of his foresight, and came across as just a tad smug.

Osborne went for the populist approach. Voters knew from their own experience that the "sooner you deal with a debt problem, the better", the shadow chancellor said. "We need to cut wasteful government spending instead of increasing national insurance taxes on hardworking people," he added. That may go down well on the doorsteps in the coming weeks, but it is economic nonsense. If the government cuts spending when households are tightening their belts, it simply leads to lower demand and a longer, deeper recession, as Darling, in one of his better interventions, pointed out.

The chancellor's team got in some early spin, saying that preparing for the budget meant their man was under-cooked. He looked it, stumbling over his lines at times and looking uncharacteristically nervous.

The dog that didn't bark was VAT. Pressed to rule out higher VAT, Darling and Osborne used the traditional formula that they had no plans to raise the tax. But that was what Margaret Thatcher said before the 1979 election. She raised it six weeks after polling day.